Devils Thumb[1], or Taalkhunaxhkʼu Shaa in Tlingit, is a mountain in the Stikine Icecap region of the Alaska–British Columbia border, near Petersburg. It is named for its projected thumb-like appearance. Its name in the Tlingit language has the meaning "the Mountain That Never Flooded" and is said to have been a refuge for people during Aangalakhu ("the Great Flood"). It is one of the peaks that marks the border, and is also listed on maps as Boundary Peak 71.

Devils Thumb is a very challenging climb even for advanced mountain climbers. A description of the mountain can be found in Eiger Dreams, a collection of articles by Jon Krakauer, who climbed the mountain early in his career. Krakauer also chronicles his solo ascent of Devils Thumb in chapters 14 and 15 of his book Into the Wild.

The most famous feature on the Devils Thumb among climbers is its Northwest Face, rising 6,700 ft (2,042 m) from the Witches Tits at its base to the summit, at an average angle of 67 degrees. This is the biggest rock face in North America. The conditions prevalent also make it perhaps the most dangerous climbing proposition on the continent.

The first ascent of the Devils Thumb was a landmark in North American mountaineering. Fred Beckey, along with Clifford Schmidtke, and Bob Craig, climbed the East Ridge, a route that combined technical difficulty equal to anything ever climbed on the continent to that time with great remoteness and terrible weather conditions.